1. Field of the Invention
The present invention relates to an image forming apparatus, a method of suctioning liquid from nozzles of a recording head of the image forming apparatus and a computer readable information recording medium; and in particular, to an image forming apparatus having a recording head that discharges liquid droplets, a method of suctioning liquid from nozzles of the recording head of the image forming apparatus and a computer readable information recording medium storing a program for carrying out the method.
2. Description of the Related Art
An image forming apparatus can be, for example, a printer, a facsimile machine, a copier, a plotter, or a multi-function peripheral in which some functions of a printer, a facsimile machine, a copier, a plotter, and so forth, are combined. As such an image forming apparatus, an ink jet recording apparatus is known, for example. An ink jet recording apparatus is known as an image forming apparatus of a liquid discharge recording type using a recording head that is configured as a liquid discharge head (or a liquid droplet discharge head) that discharges ink droplets. In such an image forming apparatus of the liquid discharge recording type, ink droplets are discharged by a recording head onto a sheet of paper that has been conveyed, so that an image is formed on the sheet of paper. Forming an image may also be referred to as recording, printing or such. Image forming apparatuses of the liquid discharge recording type include a serial-type image forming apparatus and a line-type image forming apparatus. The serial-type image forming apparatus is such that a recording head moving in main scan directions discharges liquid droplets and forms an image. The line-type image forming apparatus is such that a line type recording head is used where the recording head not moving discharges liquid droplets and forms an image.
It is noted that in the present Patent Application, an “image forming apparatus” of the liquid discharge recording type means an apparatus that discharges liquid to a medium such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics or such. “Forming an image” means not only giving to a medium an image that has a meaning such as a letter, a figure or such, but also giving to a medium an image that does not have a meaning such as a pattern or such (also means merely causing a liquid droplet to land on a medium). “Ink” means not only one called “ink”, but is used as a general term for any thing that is capable of being used to form an image, such as one called recording liquid, fixing solution, liquid or resin. Further, “sheet of paper” is not limited to one made of a paper material, includes an OHP (Over Head Projector) sheet, cloth or such, has a meaning of one to which an ink droplet adheres, and is used as a general term for any thing including one called a to-be-recorded-on medium, a recording medium, recording paper, or such. Further, an “image” is not only a planar image but also an image given to a thing that has been formed three-dimensionally, or a statue or such having a three-dimensional shape formed as a result of being molded three-dimensionally or so.
In an image forming apparatus of the liquid discharge recording type, a maintenance and recovery mechanism may be provided for the purpose of maintaining stability in discharging liquid droplets from nozzles of a recording head, and preventing ink in the nozzles from being dried and preventing dirt/dust from entering the nozzles. The maintenance and recovery mechanism includes a cap that caps a nozzle face of the recording head, and a wiper member (which may be called a wiper blade, a wiping blade or a blade) that wipes and cleans the nozzle face of the recording head. For example, after the ink having increased viscosity is discharged from the nozzles into the cap, a recovery operation is carried out in which the nozzle face is wiped by the wiper member, and nozzle meniscuses are created.
As such a maintenance and recovery mechanism in the related art, one is known in which a suction pump made of a tube pump is provided in a discharge path that is used to discharge the ink from the cap (see Japanese Laid-Open Patent Application No. 2010-000780 (Patent Document 1)). In this maintenance and recovery mechanism, a driving force transmission mechanism is provided whereby a motor that is a single driving source carries out moving the cap and rotating the tube pump. In this maintenance and recovery mechanism, the suction pump is driven when the motor is rotated in a normal direction, and the cap is moved (raised and lowered) when the motor is rotated in a reverse direction.
As another example of such a maintenance and recovery mechanism in the related art, one is known in which an open/close valve is provided between a cap and a suction pump (see Japanese Laid-Open Patent Applications Nos. 2007-160793 and 2010-120266 (Patent Documents 2 and 3)).